What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Hypertension (n=731). Intervention: Seasonality (daylight hours) and air pollutants. Primary outcome: Carotid-femoral pulse wave velocity (cf-PWV) association with daylight hours (β -0.170, 95% CI -0.273 to -0.067, p=0.001).

February 23, 2017Open Access

Impact of seasonality and air pollutants on carotid-femoral pulse wave velocity and wave reflection in hypertensive patients

MPMarina Di PillaUniversity of Pisa RBRosa María BrunoVascular Medicine FSFrancesco SteaUniversity of Pisa

Key Result

Daylight hours were independently and inversely associated with carotid-femoral pulse wave velocity (β -0.170) in hypertensive patients, indicating a marked seasonality of arterial stiffness.

Study Design

Type

Cross-Sectional (n=731)

Multicenter

Structured PICO

Does seasonality and exposure to air pollutants affect carotid-femoral pulse wave velocity and wave reflection in hypertensive patients?

Population

731 hypertensive patients (314 untreated, 417 treated with antihypertensive drugs), aged 30-88 years (mean age 55.7), 58.1% male, evaluated in an outpatient clinic in Italy. Inclusion criteria: age ≥18 years, arterial hypertension (BP ≥140/90 mmHg or current antihypertensive treatment). Exclusion criteria: severe chronic heart failure, hepatic insufficiency, end-stage renal disease, active neoplastic disease, atrial fibrillation.

Intervention

Exposure to seasonality (daily number of daylight hours) and acute variations in outdoor temperature and air pollutants (PM10, O3, CO, N2O) on the day of measurement.

Outcome

Carotid-femoral pulse wave velocity (cf-PWV) and central pressure augmentation (Augmentation Index and Augmentation Pressure) measured by arterial tonometry.surrogate

Arterial stiffness, measured by pulse wave velocity, exhibits marked seasonality in hypertensive patients and may be acutely increased by environmental ozone exposure in women and untreated patients.

Main Result

Effect estimate: β -0.170 (95% CI -0.273 to -0.067)

p-value: p=0.001

Limitations

Cross-sectional design
Lack of objective measurements of 24h-BP
Unavailability of PM 2.5 and air metals data
Lack of oxidative stress markers
Lack of objective evaluation of sodium intake, physical activity, sleep duration and vitamin D levels

Abstract

OBJECTIVE: The effects of seasonality on blood pressure (BP) and cardiovascular (CV) events are well established, while the influence of seasonality and other environmental factors on arterial stiffness and wave reflection has never been analyzed. This study evaluated whether seasonality (daily number of hours of light) and acute variations in outdoor temperature and air pollutants may affect carotid-femoral pulse wave velocity (PWV) and pressure augmentation. DESIGN AND METHOD: 731 hypertensive patients (30-88 years, 417 treated) were enrolled in a cross-sectional study during a 5-year period. PWV, central BP, Augmentation Index (AIx) and Augmentation Pressure (AP) were measured in a temperature-controlled (22-24°C) room. Data of the local office of the National Climatic Data Observatory were used to estimate meteorological conditions and air pollutants (PM10, O3, CO, N2O) exposure on the same day. RESULTS: PWV (mean value 8.5±1.8 m/s) was related to age (r = 0.467, p<0.001), body mass index (r = 0.132, p<0.001), central systolic (r = 0.414, p<0.001) and diastolic BP (r = 0.093, p = 0.013), daylight hours (r = -0.176, p<0.001), mean outdoor temperature (r = -0.082, p = 0.027), O3 (r = -0.135, p<0.001), CO (r = 0.096, p = 0.012), N2O (r = 0.087, p = 0.022). In multiple linear regression analysis, adjusted for confounders, PWV remained independently associated only with daylight hours (β = -0.170; 95% CI: -0.273 to -0.067, p = 0.001). No significant correlation was found between pressure augmentation and daylight hours, mean temperature or air pollutants. The relationship was stronger in untreated patients and women. Furthermore, a positive, independent association between O3 levels and PWV emerged in untreated patients (β: 0.018; p = 0.029; CI: 0.002 to 0.034) and in women (β: 0.027; p = 0.004; CI: 0.009 to 0.045). CONCLUSIONS: PWV showed a marked seasonality in hypertensive patients. Environmental O3 levels may acutely reduce arterial stiffness in hypertensive women and in untreated patients.

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Cite This Study

Pilla et al. (Thu,) conducted a cross-sectional in Hypertension (n=731). Seasonality (daylight hours) and air pollutants was evaluated on Carotid-femoral pulse wave velocity (cf-PWV) association with daylight hours (β -0.170, 95% CI -0.273 to -0.067, p=0.001). Daylight hours were independently and inversely associated with carotid-femoral pulse wave velocity (β -0.170) in hypertensive patients, indicating a marked seasonality of arterial stiffness.

synapsesocial.com/papers/6a1cac02c9d372840a89940a https://doi.org/https://doi.org/10.1371/journal.pone.0172550

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